math: change oeis.org urls to https

Regular HTTP is insecure, oeis.org supports HTTPS and it is actually
used in some other places in the codebase. This changes these final urls
to use HTTPS.

Change-Id: Ia46410a9c7ce67238a10cb6bfffaceca46112f58
Reviewed-on: https://go-review.googlesource.com/52072Reviewed-by: Alberto Donizetti <alb.donizetti@gmail.com>

src/math/const.go

@@ -9,18 +9,18 @@ package math
 
 // Mathematical constants.
 const (
-	E   = 2.71828182845904523536028747135266249775724709369995957496696763 // http://oeis.org/A001113
-	Pi  = 3.14159265358979323846264338327950288419716939937510582097494459 // http://oeis.org/A000796
-	Phi = 1.61803398874989484820458683436563811772030917980576286213544862 // http://oeis.org/A001622
+	E   = 2.71828182845904523536028747135266249775724709369995957496696763 // https://oeis.org/A001113
+	Pi  = 3.14159265358979323846264338327950288419716939937510582097494459 // https://oeis.org/A000796
+	Phi = 1.61803398874989484820458683436563811772030917980576286213544862 // https://oeis.org/A001622
 
-	Sqrt2   = 1.41421356237309504880168872420969807856967187537694807317667974 // http://oeis.org/A002193
-	SqrtE   = 1.64872127070012814684865078781416357165377610071014801157507931 // http://oeis.org/A019774
-	SqrtPi  = 1.77245385090551602729816748334114518279754945612238712821380779 // http://oeis.org/A002161
-	SqrtPhi = 1.27201964951406896425242246173749149171560804184009624861664038 // http://oeis.org/A139339
+	Sqrt2   = 1.41421356237309504880168872420969807856967187537694807317667974 // https://oeis.org/A002193
+	SqrtE   = 1.64872127070012814684865078781416357165377610071014801157507931 // https://oeis.org/A019774
+	SqrtPi  = 1.77245385090551602729816748334114518279754945612238712821380779 // https://oeis.org/A002161
+	SqrtPhi = 1.27201964951406896425242246173749149171560804184009624861664038 // https://oeis.org/A139339
 
-	Ln2    = 0.693147180559945309417232121458176568075500134360255254120680009 // http://oeis.org/A002162
+	Ln2    = 0.693147180559945309417232121458176568075500134360255254120680009 // https://oeis.org/A002162
 	Log2E  = 1 / Ln2
-	Ln10   = 2.30258509299404568401799145468436420760110148862877297603332790 // http://oeis.org/A002392
+	Ln10   = 2.30258509299404568401799145468436420760110148862877297603332790 // https://oeis.org/A002392
 	Log10E = 1 / Ln10
 )